: : You might have a roof vent problem (frozen or blocked) and its just showing up in the drains. The vent allows outside air to flow into and out of the waste pipes of your home, without siphoning the water that seals each household drain down the waste pipes. The vent should be sized large enough to allow flushing a toilet and draining another sink or tub at the same time, without disturbing the water seals in the rest of the house. Use a flashlight to look down at the water surface in another drain as someone elsewhere flushes a toilet. The water in the drain should not move or bubble. A restriction or blockage in the vents will show up as smelly gas vented into the living areas from a drain. Evaporation of the seal water will take some time, probably more than two weeks but you should check each unused drain has enough wateri have the same problem,the following took care of the stinch in the house; i was told that on a slab floor wax rings arent perfect you need to seal around the bowl to floor with rtv or similar, i did and that was it. iwas also told if the extension of the vent pipe to 3 did not cure the outside smell to run two 90 deg elbows right off the short pipe to form a U bend this is said to slow down the flow of gas yet allow air to escape tried it last night and so far it seems to work time will tell but it only ran agout 4 bucks for the 3 fittings in pvc so what the heck.(i believe this config. is used on gas wells)
